Comcast is joining Apple and Google in the race to convince customers that they need Internet-connected smart home devices like thermostats, lights and garage door openers.

Comcast begins a new program Friday, Works with Xfinity Home, desinged to give customers the option of controlling all of their smart home devices using a single mobile app and password. As it is, many smart home devices require separate apps and log-ins, creating a headache for consumers.

The Philadelphia company’s first four partnerships for the Works with Xfinity Home program include Google’s Nest Learning Thermostat and a smart door lock made by San Francisco startup August.

“We want to make the connected home something that is approachable,” said Daniel Herscovici, senior vice president and general manager of Xfinity Home. “And to do so, we want to make it wicked easy, to make devices talk to each other, to make installation, setup and support easy.”

The market for these Internet-connected, sensor-packed appliances is still in its infancy. And a Los Gatos research firm Argus Insights said sales are stalling because average homeowners still don’t see the need to buy them.

But another recent industry forecast projected that the market could generate $17.5 billion by 2019. So tech giants Apple and Google have both launched initiatives designed to make thousands of smart home devices compatible with their software platforms.

Comcast’s entry could give the market another boost because of its reach with mainstream cable TV and high-speed Internet subscribers. Comcast can also flex its marketing power through its media conglomerate, NBCUniversal.

Smart home devices may also give Comcast another layer of technology to lure new customers to its growing home security service, even as its pay-TV service loses subscribers. But Herscovici said Comcast views home security and automation as a fourth line of business and not as a hedge against declining revenue from the cord-cutting trend.

“Over the next 48 months, we believe home automation as a stand-alone experience will become a large part of the customer experience,” Herscovici said. “We’re setting us up to be well positioned there.”

To earn a “Works with Xfinity Home” label, Herscovici said, smart home devices must pass a certification program run by Comcast engineers.

This isn’t a novel approach: Apple’s “Works with Apple HomeKit” and Google’s “Works with Nest” labels are also supposed to tell customers whether the third-party smart home device is compatible with their software platform of choice.

In addition to deciphering which devices work with each other, Argus also found that people believe the new smart devices are too hard to install or to use, and their novelty wears off after a while.

Comcast is tying home automation into its existing Xfinity Home security service, which has more than 500,000 subscribers. That service starts at $40 a month and includes 24-hour professional security monitoring, an alarm system and video cameras.

But Comcast is now marketing a separate $20-per-month automation-only service, called Xfinity Home Control, that includes some security devices like motion detectors and a non-Nest wirelessly controlled thermostat. Both services include a free help line for troubleshooting problems.

Herscovici demonstrated how the Xfinity Home iOS or Android app that controls the security services can also close a garage door, set the thermostat, turn on lights and unlock the front door.

The new program includes the Nest thermostat, but not yet Nest’s smoke and carbon dioxide detectors. Also included are Chamberlain’s MyQ garage door controller and a Lutron Caseta light controller and dimmer.